Diving helmet and air supply system



June 2, 1970 F. A. PARKER DIVING HELMETv AND AIR SUPPLY SYSTEM Filed Aug. 30, 1967 ZWOrXO .PW to Nq NS /N VE/v ron:

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Patented June 2, 1970 3,515,133 DIVING HELMET AND AIR SUPPLY SYSTEM Frederick A. Parker, Broomall, Pa., assignor to General Electric Company, a corporation of New York Filed Aug. 30, 1967, Ser. No. 664,448 Int. Cl. A62b 7/04 U.S. Cl. 128-142.2 1 Claim ABSTRACT OF THE DISCLOSURE Closed diving dress provided with supplies of diluent or normal air and of oxygen in separate tanks has electrical power supply and control system and pumps which maintain in the suit both water and breathing air pressure exceeding by predetermined constant amount the changing external water pressure, to simulate the stiffness of a space suit for training purposes. Carbon dioxide is absorbed and oxygen added to maintain suitable concentration; inhalation and exhalation are assisted by pump. Water circulated in suit is heated to minimize divers heat loss. There is an underwater diving helmet and a powered system to supply breathing fluid thereto. Breathable air is forcibly pumped to the helmet and extracted therefrom. This is done by a pressure sensing control diaphragm switch which senses the difference in pressure between ambient water pressure and the air pressure supplied to the helmet. When the air pressure is greater an electrical motor is operated to move a reversible valve in one direction and when the water pressure is greater the reversible valve is moved in the opposite direction. This reversible valve is connected to a continuously running water pump which pumps water to vone side of a second pressure sensitive diaphragm. The latter diaphragm is connected to the breathing fluid supplied to the helmet and, depending on the pressures subjected to, will forcibly supply or exhaust the breathing fluid to the helmet.

This invention pertains to the art of diving and the specialized apparatus therefor known generally as diving dress, including means for respiration under water.

The older apparatus for sustained diving is a flexible suit with a rigid helmet supplied with air for respiration by a hose fed from a source at the surface, the diver being weighted so he can walk on the bottom. More recent is self-contained underwater breathing apparatus which provides the diver with air from a pressurized tank through some form of regulator which approximately equilibrates the pressure of the air supplied to that of the ambient water, regardless of depth changes. Ordinarily, such apparatus comprises a mouth piece for breathing, with a faceplate to permit normal vision by shielding the divers eyes from contact with the surrounding water, the diver being left otherwise unencumbered for swimming. Socalled wet suits, usually of foam elastomer such as rubber, may be provided for thermal insulation, but are ordinarily independent of the breathing apparatus. Since the divers active working time tends to be limited by the effort required to inhale and exhale the abnormally dense air (eg. 13 times normal surface density at 400 feet), it has been taught to provide powered means to assist inhalation, and, in some cases, give some assistance in exhalation. However, the pressure differentials the diver has been required to overcome have remained rather considerable. Since the diver actually consumes only oxygen, exhaling carbon dioxide, it is uneconomical to supply his oxygen bles is objectionable. Thus the prior art includes various teachings for providing pure oxygen to replace that consumed, and absorbing the carbon dioxide. However, in the absence of automatic means to provide additional diluent when the diver descends to greater depths, such devices are convenient only for relatively shallow depths. p

A particular recent known use of underwater diving apparatus has been to train human beings to work in space in a gravity-free environment such as would be experienced in space. To this end, the diver is so ballasted as to be in neutral equilibrium and thus experiences the gross effects of weightlessness, although immersion does not duplicate the more subtle effects of true weightlessness in which, for example, the internal organs do not press on the body structure with their normal weight. However, a space suit is surrounded by vacuum and has inside it a pressure of several pounds per square inch of atmosphere. This produces a peculiar stiffness or resistance to deflection in the space suit which neither exposure to the surrounding water without a suit nor inclosure in a conventional flexible suit adequately duplicates. Also, in either case, the diver is subjected to a severe heat loss to the surrounding water which, because of the high heat transfer rates which exist between solids and liquids, is much greater than that which he would experience in a space suit, and has been found, at greater depths, to be of the order of 500 watts (430 kilogram calories per hour) or more. Since this in one hour equals about one eighth of the daily food requirement of a vigorous man engaged in heavy labor, it is evident that it constitutes, quite apart from any problems of simulation, an energy drain additional to the divers requirements for muscular activity which will not only decrease his efficiency and make him highly uncomfortable, but `will necessarily limit his possible tour of active duty.

The general object of my invention is to avoid the disadvantages of the prior art devices in a device which may be used to permit free diving (that is, without a tethering connection to the surface) at varying depths under conditions of greater physical comfort and less effort than the prior art equipments permit.

Specifically, I provide a flexible water-impervious suit connected to a rigid helmet; pumping and control means to maintain, in the suit proper, water under a predetermined excess of pressure over the surrounding water; and pumping and control means to maintain, in the helmet, oxygen at approximately the partial pressure found on earth and diluent gas at the partial pressure required to provide the desired total pressure level. Very slight pressure changes produced by the divers efforts to inhale or exhale cause pumping means to assist the inward or outward flow of gas into or out of the helmet in exact accord with his own breathing effort; and as part of the means for doing this I provide means for measuring and recording indications of the divers breathing rate and the rate at which he consumes oxygen. Furthermore, I provide means for heating the water fed into the suit.

For better understanding of my invention I have provided a figure of drawing representing schematically the relationship of the various previously known mechanical elements comprising an embodiment of my invention.

Referring to the figure, there is represented a waterimpervious suit 10 equipped with a helmet 12 having a lower part 14 permanently connected to the suit 10 and an upper part 16 which is fastened by some clamping means 18 which is indicated as a diametral double line across the helmet and may conveniently be a toggleoperated clamping ring, which renders the helmet hermetically closable. Helmet 12 is represented as equipped with a manually operated purge valve 20 which may be operated on first immersion to bleed air from the suit 10 to permit it to fill with water, or fill to some convenient level such as a face or neck seal. A breathing mouth piece 22 is represented simply as a rectangle inside the helmet 12, since its form may vary to encompass any of the standard designs of the art, and its connecting hose, or, more generally, breathing iluid conduit 24 will Ordinarily be flexible within the suit. A hydraulic connection 26 to the interior of the suit is connected to a hydraulic hose line 28. These are the elements of the suit itself; the other elements to be described will in practice conveniently be incorporated in a back pack which will ordinarily be mechanically connected to the suit as a matter of design.

The major unit of the hydraulic system is a pump 30, which may conveniently be a centrifugal pump, driven by a motor or other suitable electrical power means 32, which is powered by a power source not shown, but incorporated in rectangle 34, back pack unit which also includes electronic control devices and a recorder. The suction and discharge connections of pump 30 are connected respectively to opposite ports 38 and 40 of electrically operable four-port reversible valve 36. As may be seen from the schematic representation, which is based upon a conventional rotating-plug embodiment of such a valve, in the position shown port 38 is connected to port 42 and port 40 is connected to port 44. A quarter turn rotation of the valves central plug will connect port 38 to port 44 and port 40 to port 42. Valve 36 is represented as driven by motor 46, which may be connected by switch 120 or switch 122 to back pack unit 34. In view of the limited rotation required, motor 46 need not be a conventional motor, but may be a limited-angle rotator having a permanent-magnet armature arranged to rotate between two electromagnet poles in a direction determined by selective operation of one electromagnet or by the polarity of the current fed to the windings of the electromagnets; or two separate rotators, one for each direction, may be used. Alternatively, four-port valve 36 may be a slide valve of the kind conventional in hydraulic systems, driven by a linear thrust device.

Port 42 of valve 36 is connected through check valve 54 to hose 50, which extends to heating means in back pack unit 34. (Valve 60 is closed for the present mode of operation.) In general, since an electrical power source must be provided for convenient operation of various other devices, it may be expected that a simple electrical resistance type heater of conventional design will be conveniently employed. It is, however, to be recognized that chemically reactive mixtures are known which react exothermally; and such mixtures could be provided in replaceable sealed cartridges which, by conventional connecting means, could be replaced more rapidly than a battery could be recharged, so that they might be preferable for particular applications. Regardless of the source of heat, the circuit from hose 50 through the heating means continues via hose 28 and returns thence to connection 26, which permits the entry of heated water into the interior of suit 10. (Suitable internal water distribution means which may comprise closed extensible heat exchanger means may be provided to distribute heat throughout the suit.) The hose line 50 is also connected to adjustable relief valve 52. Check valve S6 is also connected to port 42 of valve 36. When pump 30 is started, with the valve 36 in the position shown, water will flow through check valve 56 to port 42 of valve 36, through valve 36 to port 38 and thence to the suction end of pump 30, which will discharge it via ports 40 and 44 of valve 36 to ll a part of the system to be described hereinafter. When valve 36 is rotated a quarter of a turn (responsively to control signals generated in a manner to be described hereinafter) the suction end of pump 30 will be connected via ports 38 and 44 to the part of the apparatus to which it has previously fed water, and will discharge the water from its discharge end via ports 40 and 42 of valve 36 through check valve 54 into hose line 50 through the heat exchanger means in back pack unit 34, into hose line 28, and thence via 26 into the suit 10, displacing air through bleed valve 20. (The diver may open valve 20 sufficiently long to fill the suit to some desired level and then close it.) Since (as the subsequent description will make clear) valve 36 is rotated from one position to the other each time the driver inhales or exhales, there will be a cyclical intake of water via check valve 56 and a subsequent pumping of water into suit 10 until the pressure in suit 10 has built up to a value at which adjustable relief valve 52 will open and discharge the excess of water out into the surroundings. Pump 30 runs continuously and is preferably designed to provide a maximum discharge pressure somewhat higher than the desired pressure inside suit 10. Adjustable relief valve 52 is adjusted to discharge at the desired pressure difference (e.g. 3.5 pounds per square inch) a su'iicient volume of water to maintain the suit pressure at the desired value with respect to the outside water. Valve 52 is represented schematically as a conventional form of diaphragm valve with adjustable spring loading, the spring side of the diaphragm being exposed to the pressure of the external water through opening 58 so that its setting determines the dilference between the absolute external water pressure and the internal suit pressure at which it opens.

The general arrangement of the breathing mixture system is as follows: Mouthpiece 22 is connected by hose 24 to two parallel llow paths, the first, for exhalation, being simply through check valve 62 and water extractor 64, the second, for inhalation, being through check valve 66 and carbon-dioxide absorbing lter 68 in series. Water extractor 64 is useful simply to remove any stray slugs of water which enter the system from mouthpiece 22, and may consist of a capped cylinder with suitable inlet and exit connections, containing a suitable capillary absorber such as a sponge, or may simply be a chamber 'with centrally located inlet and exit, and sufficient volume so that it can contain a usefull volume of extracted water without having the water level rise to the level of the inlet and exit. Filter A68 is simply a conventional closed container for holding an absorber for animal metabolic products to be removed which, so far as present knowledge extends, consist only of carbon dioxide inthe present application.

Both these parallel paths lead back via hose or tube 70 to hydraulically driven diaphragm-type gas pump 72 whose gas chamber 74 is fed gas from lever-operated breathing uid mixture replenishment valve 76 whenever the diaphragm 78 of pump 72 rises above a certain predetermined displacement. The volume of gas chamber 74 is deliberately made a number of times the volume of a normal inspiration, so that it contains a reserve supply of breathing mixture. This has the advantage that the frequency of operation of valve 76 is appreciably less than the breathing rate; and it also permits moderate changes in operating depth to be accommodated without the necessity of venting excess gas for a decrease in depth, or of adding breathing mixture through valve 76 for increase in depth. A bleed valve 80` is provided for venting air from the lower chamber 82 of pump 7-2, which is connected by hose or tube line 84 to port -44 of fourport valve 36. The feed to valve 76 may be of breathing mixture fed through automatically closing quick-disconnect coupling 86 through pressure regulator 88 and valve 90 from a breathing air (or, more generally, breathable fluid) tank 92. Such a supply is useful both for initially charging the air system with air or for emergencies in the event that some part of the more sophisticated oxygen replenishment system should fail. However, the intended normal mode of operation is by supply of oxygen through pressure regulator 94 and solenoid valve 96, from low volume oxygen tank 98. To effect the addition of oxygen as required, the outlet side of solenoid valve 96 is connected directly to the gas-system side 74 of diaphragm 78. An oxygen partial pressure sensor 97 is connected to the gas system in the line 70v from pump 72 to the diver. Whenever the partial pressure of oxygen in the gas system falls unacceptably low, the output signal of partial pressure sensor 97 indicates this fact, and causes control circuitry in back pack unit 34 to cause solenoid valve 96 to open and emit oxygen directly into the gas chamber 74 of pump 72. The divers normal inhalations will cause samples of gas from the gas chamber 74 to be drawn past the partial pressure sensor 97 which, when it senses that the oxygen content of the breathing mixture has been raised to the maximum acceptable value, will provide back pack unit 34 with a signal indicative thereof, and circuitry in back pack unit 34 will permit solenoid valve 96 to close. Since the consumption of oxygen during a given breath is only a small fraction of the total volume of gas inhaled, at normal atmospheric pressure, and decreases in proportion to the growth of pressure, the admission of oxygen directly into the low-pressure breathing circuit does not impair the metering effect produced by the operation of pump 72. Introduction of oxygen into the low-pressure system is desirable for a particular reason. If the diver rises suddenly, the gases in the lowpressurevbreathing system will expand, and be vented through valve 100. Under these conditions diaphragm 78 will not rise high enough to operate the lever of leveroperated valve 76; if reliance were placed on ow of oxygen from the high-pressure side of valve 76, the diver would be deprived of oxygen during his ascent.

When the apparatus is employed to simulate conditions in a space suit, it is desirable to measure and record the divers oxygen consumption. This is accomplished by making tank 98 small in comparison with the total volume of oxygen carried by the diver. A pressure transducer 102 is connected to measure the oxygen pressure in tank 98, and its signals are conveyed to the electrical control system in back pack unit 34, which is designed to open solenoid valve 104 whenever the pressure in tank 98 falls to such a value that it needs to be recharged with oxygen from oxygen supply tank 106, which is connected through valve 108 to the input side of solenoid valve 104, to pressure gauge 110, and to pressure regulator 112. The low-pressure, or regulated, side of regulator `112 is connected through emergency valve yi114 directly to the parallel circuits consisting of check valve 62 and water extractor `64, and of check valve 66 and ilter 68.

AIn an emergency during shallow water diving (e.g. 30

feet) and when accessory tank 92 is not connected, it is possible by manually operating valve 114 to feed oxygen directly from tank 106 bypassing valve 104 and pressure regulator 94.and solenoid valve 96. This mode of operation is not the normal one, but is provided for safety. Relief valve 100 is connected to the parallel paths, its diaphragm being subjected on one side to the pressure of water inside the suit via hoses 28 and 501, the other side being subject to the pressure in the gas system, rising to discharge gas from the gas system whenever the pressure in the gas system is, for any reason, more than a safe value (e.g. one-half pound per square inch) above the suit pressure. Valve 100 will vent excess pressure if the regulating system fails, or if the diver rises through the water to a level where the water pressure is sufficiently lower so that the reserve expansion volume 74 in diaphragm pump 72 is inadequate.

The normal mode of operation of the interacting hydraulic and gas systems depends upon differential pressure switch unit 116. This may be, and is represented as, a diaphragm-operated switch unit having the lower side of its diaphragm or pressure difference sensing control 118 exposed to the pressure of water fed to suit "10` through hose 28, and having its upper side exposed to the pressure of air fed to mouthpiece through hose 24. When the air pressure is greater than the water pressure, the diaphragm is moved downward and closes lower switch 120; and when the air pressure is less than the water pressure, the diaphragm is displaced upward to 6) close upper switch 122 contacts. Assuming that the air and water pressures are initially equal, when the diver inhales, reducing the pressure in hose 24, the diaphragm of control 116 will move upward, closing its upper switch 122. This will close a circuit from back pack unit 34 which will operate motor 46 so as to turn valve 36 to the position represented in the iigure. Water at the discharge pressure of pump 30 will then be applied to diaphragm 78 of pump 72, causing it to move upward and force breathing mixture from its upper chamber 74 through filter 68 (which absorbs any carbon dioxide) and check valve 66 through hose 24 to mouthpiece 20'. Thus the diver need produce initially only the slight vacuum required to operate switch unit 116 (which may be of the order of one-tenth of a pound per square inch) to be supplied with breathing air. Check valve 62 will be closed during this part of the cycle. When the diver subsequently exhales, raising the pressure slightly in mouthpiece 22 and hose 24, diaphragm 118 will be depressed, closing lower switch 120. This, by its connection to back pack unit 34, will cause motor 46 to turn in the proper direction to place valve 36 in its alternate position, not here represented, causing the intake end of pump 30 to be connected to pump 72 and apply suction to the diaphragm 78, causing diaphragm 78 to move downward, creating a vacuum which will withdraw the exhaled mixture through check valve 62 from mouthpiece 20 via hose 24. Thus the divers exhalation is assisted by the action of pump 72. Check valve 66 will be closed during this part of the cycle. It is evident that the divers breathing, both inhalation and exhalation, need be only against the small pressure difference required to move diaphragm 1118. When consumption of oxygen causes partial pressure sensor 97 to cause solenoid valve 96 to open and admit oxygen to the lowpressure system, it flows through pressure regulator 94 from oxygen tank 98, causing a reduction in the pressure in tank 98 which is sensed by pressure transducer 102, which transmits to the circuitry in back pack unit 34 a signal representative of the reduced pressure. A recorder may be incorporated in back pack unit 34 to record the pressure existing in tank 98 at any moment; andwhen the pressure in tank 98 falls to a predetermined lower value (still high enough to operate pressure regulator 94 and feed oxygen to valve 96 and thence to the diver) circuitry in back pack unit 34 causes solenoid Valve 104 to open, permitting oxygen to flow from supply tank 106 through valve 108 and into tank 98 until pressure transducer 102 signals that the pressure in tank 98 has reached a predetermined upper limit, responsively towhich the circuitry in back pack unit 34 permits solenoid valve 104 to close. Since the record of the pressure variations in tank 98 indicates the rate of consumption of oxygen from tank 98, and also how often tank 98 is refilled from tank 106, by recording the indications of transducer 102 in a recorder in back pack unit 34 a complete record of the rate of oxygen consumption by the diver is provided. The sensitivity of the system may be adjusted by making tank 98 sufliciently small so that the withdrawal of a given volume of air to be measured will produce a pressure change in the tank 98 suiciently great to be readily sensed and recorded accurately. Putting filter 68 in the inhalation circuit has the advantage that the air to be breathed is ltered as close as possible to the point of consumption;

it could be placed in series with check valve 62 in ther exhalation circuit.

Since the partial pressure of oxygen is limited to approximately that existing in the atmosphere at the earths surface, it is necessary to add a diluent gas to compensate for increases in pressure as the diver descends, or to replace gas which may be leaked from the system. Diluent tan-k 124, connected through manual valve 126 and pressure regulator 128 to lever-operated valve 76, provides this function. If the residual gas in the upper chamber 74 -of diaphragm pump 72, including any oxygen supplied through solenoid valve 96, is too` small to produce pressure adequate to keep diaphragm 78 in its approximately normal range of motion, diaphragm '78 will rise enough to operate the lever lof lever-operated valve 76, and admit diluent gas from tank 124 in sucient volume to allow diaphragm 78 to return to its normal range of motion. The frequency of this action will depend upon the tightness of the helmet and its connections, and the extent to which the diver remains at an approximately constant depth. If he descends, diluent must be admitted; when he ascends again, breathing air, including both diluent and oxygen, will be vented through valve :100 (assuming he exceeds the reserve capacity or volume in the diaphragm pump, gas chamber 74); if he then again descends, more diluent will be consumed. Thus each descent and ascent beyond the designed reserve volume constitutes a cycle of drain upon the diluent supply.

It is evident that the various features of my invention other than those whose sole function is to assist in the pressurization of the suit are useful for general diving purposes. Obviously, the adjustment of valve 52 so that it will open at a trivial pressure differential will reduce the internal suit pressure to one negligibly different from that of the surrounding water. The recirculation of heated water which results from continuing the connection to connection 26 may well justify its continued use, although it would be possible to forego this advantage. But connection 26 (or even suit 10) and hose 28, valves 54, and 56, and relief valve `52 may simply be eliminated, port 42 of four-port valve 36 being open to the surrounding water (preferably through a strainer). The Water sides of the diaphragms of valve 100I and switch unit 122 will also be left open to the pressure of the surrounding water. This latter mode of operation will have the advantages of selfcontained breathing apparatus in which oxygen is supplied automatically as required without a substantial change in the partial pressure of oxygen within the system, and carbon dioxide is automatically absorbed; but it will have the particular novel advantages that both inhalation and exhalation occur with only slight pressure differentials in the divers lungs. (This being understood to be a particularly valuable attribute at great depths where the greatly increased density of the atmosphere otherwise causes a substantial amount of energy to be required to breathe.)

However, the embodiment represented in the figure has provision for operation with negligible pressurization of suit 10. This may be achieved by opening valve 60. Then valve 54 will be bypassed, and suit 10 will be connected for ow in both directions via connection 26, hose 28, back pack unit 34, and hose 50 to port 42 of fourport valve 36. Then, as the diver exhales a given volume of breathing mixture through mouthpiece 22, diaphragm 78 will descend to displace from chamber 82 approximately the same volume of water, which will ow into the suit 10, becoming heated in its passage through back pack unit 34. When the diver inhales, the diaphragm 78 will rise, admitting into chamber 82 an approximately equal volume of water which will ow out of suit 10. Thus there will be little occasion for discharge of Water through valve 52, since whatever water the diver displaces in inhaling will be received into chamber 82, and then returned (through the heating means in back pack unit 34) when he exhales. Thus very little heated water will be thrown away; and further breathing will not involve any major flexing of the suit, since the total volume inside the suit (volume of diver plus volume of lling Water) will remain approximately constant. It is evident that this mode of operation will minimize loss of heated water. A similar mode of operation is possible with suit 10 pressurized above the pressure of the external water by opening valve 60 and adjusting the output pressure of pump 30 to approximately that at which valve 52 is on the verge of opening. Indeed, it is possible to mount electrical contacts in mechanical connection with the diaphragm of valve 52 and use them in an on-oi servo arrangement to control the speed of motor 32 so that the output pressure of pump 30- is maintained, on the average, at the value described. This has not been illustrated because the usual purpose of pressurization is to simulate space operations; and such simulation may conveniently be done at moderate depths where water temperatures approximate surface temperatures so that heat conservation would not be so necessary as at the cold of greater depths.

What is claimed is: 1. An underwater diving helmet and breathing uid supply means comprising in combination: l

a hermetically closable helmet means adapted to be worn by a diver;

breathing fluid conduit means connected to said helmet for the ingress and egress of a breathing mixture thereto;

an electrical power means;

a hydraulic pump means operatively connected to said power means;

a reversible valve means connected to said pump means;

a pressure sensitive diaphragm means connected to said breathing iluid conduit means to forceably supply or exhaust breathing tluid to the helmet and also connected to said reversible valve means;

a filter means located in said breathing liuid conduit means between the helmet and diaphragm means;

a breathing uid mixture replenishment valve means connected to said diaphragm means;

a source of breathable fluid connected to said valve means;

a pressure difference sensing control means to sense the difference in pressure between iluid in theA divers helmet and ambient water pressure;

and switch means connected to said sensing control means to control the direction of movement of said reversal valve means depending on the pressure difference sensed.

References Cited UNITED STATES PATENTS .2,617,414 1 1/ 1952 Hollmann 12S-142.2 X I 2,830,583 4/ 1958 Finney 128--142 FOREIGN PATENTS 21,479 6/1915 Great Britain. 393/650 9/ 1924 Germany.

ANTON O. OECHSLE, Primary Examiner THOMAS ZACK, Assistant Examiner U.S. Cl. X.R. 

